The present invention relates to a dust control system, more particularly to a system of removing dust and particulate matter from a moisture-laden vapor stream that is heavily laden with particulates, such as a vapor stream leaving a dryer assembly of a waste treatment system.
Environmental concerns have motivated a search for waste disposal systems capable of disposing of waste materials in accordance with the applicable regulating standards. The most widely used of these disposal means comprises incinerating the waste materials. Incineration of such waste is most efficient if the material is dried by conveying it through a dryer where it is mixed with hot gasses prior to combustion. For example, U.S. Pat. No. 3,801,264 (Lindl) discloses a system in which waste materials are conveyed through a dryer where they are mixed with exhaust gasses from a burner before they are incinerated. This system removes the vapors exiting the dryer via a conventional fan, and passes the vapors through a single cyclone and a scrubber before they are either emitted to the atmosphere or conveyed to the inlet of the burner. But the single-step clarification process performed by this system is ineffective to adequately clean the vapor. In fact, only those particles that are heavy enough to fall out of the vapor at ordinary vapor-stream velocities are removed by the cyclone. Furthermore, the moisture-laden vapor tends to condense on the surface of the cyclone, reducing the efficiency of the clarification operation. In many instances, the scrubber is unable to remove an adequate amount of the particulates. This system is thus often incapable of removing enough particulates from the vapor to meet existing environmental standards. Moreover, this system is inherently inflexible, as its operational parameters are limited by the operational limits of the single fan.